Here students can locate TS Inter 1st Year Zoology Notes 2nd Lesson Structural Organisation in Animals to prepare for their exam.
TS Inter 1st Year Zoology Notes 2nd Lesson Structural Organisation in Animals
→ The ’tissue grade of organisation’ evolved for the first time in the cnidarians.
→ Multicellular animals without cell correlation and division of labour is seen in PORIFERA (Parazoans)
→ Tissues are Jacks of all trades and masters of none.
→ Tissues are essentially of 4 types – epithelial, connective, muscular and nervous.
→ Epithelial tissues cover the outer surfaces / free surfaces of the body organs and act as’physical barriers’.
→ Connective tissues help in binding and supporting other tissues.
→ A connective tissue has diffuse cells interspersed by ‘extracellular matrix’ made up of different types of fibres.
→ Various types of fibres are formed by cells called ‘fibroblasts’.
→ Muscular tissues are concerned with various types of movements in the body,
→ Muscles contain proteins such as ‘actin’ and ‘myosin’, which together cause contraction.
→ Muscles are 3 types – Skeletal, cardiac and smooth.
→ Skeletal and cardiac muscles are of the ‘striated’ type and smooth muscles are (also called visceral muscles) unstriated muscles.
→ Nervous tissue senses ‘stimuli’ and conducts (transmits) them in the form of’ nerve impulses from one part of the body to another.
→ Nervous tissue consists of nerve cells called ‘Neurons’.
→ Nervous tissue also contains various types of ‘glial cells’.
→ Nervous tissue is chiefly involved in bringing about co-ordination between the | activities of various body parts.
→ There are five levels of organisation. They are.
- Protoplasmic level
- Cellular level of organisation
- Tissue level of organisation
- Organ level of organisation :
- Organ-system level of organisation.
→ Marie Frangois Xavier Bichat (1771-1802):
Marie Frangois Xavier Bichat was the first person to look beyond the recognizable organ systems and suggest that each part of the body was composed of various kinds of tissues. He is considered the “father of modern histology and pathology.”
Bichat was born in Thoirette, France, in 1771, the son of a physician. In Lyons, Bichat studied mathematics and physical science before settling on the study of anatomy.
Later Bichat took his place in the medical community and continued writing, lecturing, and doing research. Using only a hand-lens, he identified 21 different kinds of tissue, such as fibrous, glandular, or mucus tissue, in the body. Bichat also studied the effects of different diseases and therapeutic agents on different tissues.
Bichat was well known as a brilliant teacher during his life. In 1800 he was appointed to serve as secretary of a medical advisory board established by the French government. By the age of 31 he had published three well-received books on tissues, general anatomy, and the physiological aspects of life and death. Today he is remembered as a physician and teacher who advanced the understanding of the connection between disease and physical changes in the body.